(HealthDay News) – For older patients with a history of myocardial infarction (MI), a high-dose oral multivitamin and multimineral mixture is safe, but does not significantly reduce cardiovascular events, according to a study published in the Dec. 17 issue of the Annals of Internal Medicine.

Gervasio A. Lamas, MD, from the Mount Sinai Medical Center in Miami Beach, and colleagues assessed the effectiveness of high-dose multivitamins for secondary prevention of atherosclerotic disease in a cohort of 1,708 patients (median age, 65 years; 18% women) from 134 academic and medical sites, who had MI at least six weeks earlier. Participants were randomized to an oral 28-component high-dose multivitamin and multimineral mixture or to placebo, and were followed for a median of 55 months.

The researchers found that 76% of the vitamin and placebo groups completed at least one year of oral therapy (P=.98), while 47% and 50%, respectively, completed three years of therapy (P=0.23). 46% in each group discontinued the regimen (P=0.67) and 17% of participants withdrew from the study. The primary end point of time to total death, recurrent MI, stroke, coronary revascularization, or hospitalization for angina occurred in 27% and 30% of those in the vitamin and placebo groups, respectively (hazard ratio, 0.89; P=0.21). In no category of adverse events was there evidence of harm from vitamin therapy.

“These conclusions must be interpreted cautiously because of a high rate of non-adherence to the study regimen,” the authors write.

One author disclosed financial ties to the pharmaceutical industry.

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